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Broadcast storm control best practice


In a switched network with a spanning tree root and backup root switch GE-channeled together and lots of switches "dual-homed" to these switches I would like to implement broadcast/multicast storm control.

I would like to errdisable the involved ports in case of a storm.

I figured that implementing broadcast storm control on all ports except the links to the root switch might be the best way (enable broadcast storm control on host ports and both ports on links to/from the backup root).

This so that in case of a spanning tree loop in the network all redundant links are disabled but the primary links and the netork will still in theory be operational.

I don?t want the entire network fragmented (which could happen if broadcast storm control is enabled on the links to the spanning tree root also) - I just want all loops to be disabled.

Any host sending large amounts of broadcasts will be disconnected.

Comments on this are wellcome.

I know how to configure it, but does anyone have any best practice for implementing broadcast storm control, On what ports to enable this feature in a trivial trianglar designed network, what thresholds/procentages to use or any other guides, thanks?

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Re: Broadcast storm control best practice

Error-disabling the ports scares me a little. We've been experimenting here, and at a 10% threshold on host ports and 15% on trunks (all gigabit), we're getting sporadic storm-control events, that I believe are false alarms (i.e., stable network, no obvious reason for the event). We send traps, but don't disable the ports. Making those go err-disable would have been disastrous for us, possibly orphaning a switch from the core.

I can't tell from your post if you're using storm-control to throttle a storm caused by a loop, or the other way around. But - wouldn't loopguard and/or UDLD perhaps fit better? I guess it depends on what you're trying to achieve.

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